Advances in the Application of Electrospun Drug-Loaded Nanofibers in the Treatment of Oral Ulcers

Advances of antimicrobial dressings loaded with antimicrobial agents in infected wounds

Wound healing is a complex process that is critical for maintaining the barrier function of the skin. However, when a large quantity of microorganisms invade damaged skin for an extended period, they can cause local and systemic inflammatory responses. If left untreated, this condition may lead to chronic infected wounds. Infected wounds significantly escalate wound management costs worldwide and impose a substantial burden on patients and healthcare systems. Recent clinical trial results suggest that the utilization of effective antimicrobial wound dressing could represent the simplest and most cost-effective strategy for treating infected wounds, but there has hitherto been no comprehensive evaluation reported on the efficacy of antimicrobial wound dressings in promoting wound healing. Therefore, this review aims to systematically summarize the various types of antimicrobial wound dressings and the current research on antimicrobial agents, thereby providing new insights for the innovative treatment of infected wounds.

Genetic Connectivity of Gut Microbiota and Oral Ulcers: A Mendelian Randomization Study

OBJECTIVES

The aim of this study was to reveal the relationship, if any, between gut microbiota and oral ulcers.

METHODS

We performed a 2-sample Mendelian randomization (MR) study to estimate the roles of gut microbiota in mouth ulcers. The summary datasets of gut microbiota were from the largest genome-wide association study (GWAS) conducted by MiBioGen, and data of mouth ulcers were obtained from UK Biobank. Random effect inverse variance-weighted, weighted median, MR Egger, simple mode and weighted mode were used to estimate the relationship. Sensitivity analyses were conducted to assess the heterogeneity and pleiotropy of instrumental variables. MR Steiger filtering was also applied to orient the causal direction.

RESULTS

Three gut microbiota taxa were positively associated with mouth ulcers: Holdemania (odds ratio [OR] = 1.005, 95% confidence interval [CI]: 1.001-1.009, P = .019), Oxalobacter (OR = 1.004, 95% CI: 1.000-1.007, P = .032), and Ruminococcaceae UCG011 (OR = 1.006, 95% CI: 1.001-1.011, P = .029), while 4 gut microbiota taxa were negatively associated with mouth ulcers: Actinobacteria (OR = 0.992, 95% CI: 0.985-1.000, P = .042), Lactobacillales (OR = 0.995, 95% CI: 0.990-1.000, P = .034), Oscillospira (OR = 0.990, 95% CI: 0.984-0.997, P = .007) and Phascolarctobacterium (OR = 0.992, 95% CI: 0.986-0.997, P = .003). Sensitivity analyses validated the robustness of the association in between.

CONCLUSIONS

This MR study identified a strong association between the quality of gut microbiota and oral ulcers. The findings are likely to expand the therapeutic targets for mouth ulcers.

Development of an innovative eugenol and borax-based orodispersible film for enhanced treatment of mouth ulcers

Orodispersible films (ODFs) have emerged as an advanced and patient-friendly delivery system due to ease of administration, improved patient compliance, quick release and taste-masking of active pharmaceutical ingredients. This research reports the preparation of the ODF containing eugenol and borax (EB-ODF) by a solvent casting technique for treating mouth ulcers. The EB-ODF consisted of vinyl pyrrolidone/vinyl acetate copolymer (Kollidon® VA64, VA64) and hydroxypropyl methylcellulose (HPMC-K250) as the film formers where eugenol and borax were loaded. The thickness of the EB-ODF obtained was 0.119 ± 0.001 mm and the tensile strength was 13.1 ± 1.1 N/mm2 (p > 0.05). The prepared films disintegrated in the oral cavity within 30 s and over 90% of the eugenol was released from the film in the first 5 min. Furthermore, the combined application of eugenol and borax, loaded in EB-ODF, displayed notable synergetic antibacterial property against both gram-negative and gram-positive bacteria. In an in-vivo study on a rat model with chemical burn-induced oral ulcers, the EB-ODF treatment group had a 100% reduction in ulcer area (p > 0.05) after 10 days of treatment and demonstrated a 38.7% higher reduction in oral ulcer area compared to the Dingpeng Cream treatment group (p < 0.0001). The EB-ODF treatment group showed minimal oral irritation, scoring only 1 point and a 65% preference in the taste tests (p < 0.0001). In summary, EB-ODF had successfully overcome the poor palatability of commercially available formulation and provided notable potential for further ulcer treatment product development.

Causal associations between estradiol and mouth ulcers: A Mendelian randomization study

People have difficulty in eating and speaking when they are suffering from mouth ulcers. Some studies suggest that estradiol is associated with the development and treatment of mouth ulcers, while some do not. To clarify the effect of estradiol on mouth ulcers, we performed 2-sample Mendelian randomization and multivariable Mendelian randomization (MVMR) analysis to evaluate their relationship. Data were obtained from the IEU OpenGWAS project and UK biobank, including male estradiol dataset (case/controls = 13,367/134,323), female estradiol dataset (case/controls = 37,461/126,524), mouth ulcers dataset (case/controls = 47,102/414,011). The causal associations were estimated by MR-Egger, weighted median, inverse-variance weighted (IVW) method, simple mode, and weighted mode. Cochran Q test, MR-Egger intercept test, MR-PRESSO tests, and leave-one-out analysis were used to examine sensitivity analyses. The MVMR controlling for depression, anxiety or panic attacks, severe stress and adjustment disorders was used to assess the effect of estradiol on mouth ulcers. Through screening, 13 single nucleotide polymorphisms (SNPs) of males and 2 SNPs of females in estradiol were used for harmonizing and MR analysis. The 2-sample MR analysis showed no causal association between estradiol of males and mouth ulcers (IVW, OR: 0.998, 95% confidence interval [95% CI]: 0.995-1.001, P = .18). Similar results were obtained between estradiol of females and mouth ulcers (IVW, OR: 1.000, 95% CI: 0.988-1.012, P = .97). No pleiotropy and heterogeneity were found and the results were robust (P > .05). After adjusting for the potential effects of confounders, estradiol of males and mouth ulcers still showed no causal association through MVMR analysis (P = .081). While MVMR analysis showed that the causal relationship between estradiol and mouth ulcers in women could not be statistical for the small number of SNPs. There was no evidence of a causal relationship between estradiol and mouth ulcers. The strategy of treating mouth ulcers with estradiol still needs to be confirmed by more studies.

One-Step Synthesis of Hydrogel Adhesive with Acid-Responsive Tannin Release for Diabetic Oral Mucosa Defects Healing

The complex preparation, weak wet tissue adhesion, and limited biological activity of traditional oral wound dressings usually impede their efficient treatment and healing for diabetic oral mucosal defects. To overcome these problems, a novel hydrogel adhesive (named CFT hydrogel) is rapidly constructed using a one-step method based on dual-dynamic covalent cross-linking. Compared with the commercial oral patches, the CFT hydrogel shows superior in vivo (rat tongue) wet tissue adhesion performance. Additionally, the CFT hydrogel exhibits unique acid-responsive properties, thereby facilitating the release of bioactive molecule tannic acid in the acidic diabetic wound microenvironment. And a series of in vitro experiments substantiate the favorable biocompatibility and bioactivity properties (including antibacterial, antioxidative, anti-inflammatory, and angiogenetic effects) exhibited by CFT hydrogel. Moreover, in vivo experiments conducted on a diabetic rat model with oral mucosal defects demonstrate that the CFT hydrogel exhibits significant efficacy in protecting against mucosal wounds, alleviating inflammatory reactions, thereby facilitating the wound-healing process. Taken together, this study provides a promising and comprehensive therapeutic option with great potential for the clinical management of oral mucosa defects in diabetic patients.

Network pharmacology-based strategy combined with molecular docking to explore the potential mechanism of agarwood against recurrent aphthous stomatitis

To explore the antiinflammatory mechanism of agarwood on recurrent aphthous stomatitis (RAS). RAS is the most common mucosal disease in the oral cavity. The clinical application of traditional Chinese medicine found that agarwood has significant curative effect on peptic ulcer, but the effect and mechanism of agarwood on RAS remain unclear. This study is intended to predict the potential antiinflammatory mechanisms by which agarwood acts on RAS through network pharmacology and molecular docking. TCMSP database was used to screen the active components of agarwood. RAS targets were screened in Genecards, DisGeNET, and OMIM database. Venny, an online tool, screens for interacting genes between the two. Cytoscape software was used to construct the gene regulation map of active compounds target of agarwood. String Database building protein-protein interaction network. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathways were enriched in DAVID database. The key active ingredients and core targets were further verified by molecular docking. There were 9 effective compounds and 186 target genes in agarwood; RAS has 793 target genes. There were 41 interacting genes between agarwood and RAS. Interleukin 6, tumor necrosis factor, interleukin 1 beta, and cellular component motif ligand 2 may be key targets. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses predicted multiple pathways associated with RAS. Molecular docking results showed that the active compounds of agarwood combined well and stably with the target. The Chinese herbal medicine agarwood can relieve the inflammation of RAS through multiple targets and various ways. Its active compounds may be nominated as candidates for antiinflammatory drugs of RAS.

Electrospun multi-chamber core-shell nanofibers and their controlled release behaviors: A review

Core-shell structure is a concentric circle structure found in nature. The rapid development of electrospinning technology provides more approaches for the production of core-shell nanofibers. The nanoscale effects and expansive specific surface area of core-shell nanofibers can facilitate the dissolution of drugs. By employing ingenious structural designs and judicious polymer selection, specialized nanofiber drug delivery systems can be prepared to achieve controlled drug release. The synergistic combination of core-shell structure and materials exhibits a strong strategy for enhancing the drug utilization efficiency and customizing the release profile of drugs. Consequently, multi-chamber core-shell nanofibers hold great promise for highly efficient disease treatment. However, little attention concentration is focused on the effect of multi-chamber core-shell nanofibers on controlled release of drugs. In this review, we introduced different fabrication techniques for multi-chamber core-shell nanostructures, including advanced electrospinning technologies and surface functionalization. Subsequently, we reviewed the different controlled drug release behaviors of multi-chamber core-shell nanofibers and their potential needs for disease treatment. The comprehensive elucidation of controlled release behaviors based on electrospun multi-chamber core-shell nanostructures could inspire the exploration of novel controlled delivery systems. Furthermore, once these fibers with customizable drug release profiles move toward industrial mass production, they will potentially promote the development of pharmacy and the treatment of various diseases. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Identification and characterization of major bioactive compounds from Andrographis paniculata (Burm. f.) extracts showed multi-biomedical applications

The Andrographis paniculata recognized as most valuable medicinal plant in folk medicine. Hence, this research was designed to evaluate antibacterial potential of petroleum ether (PE) and methanol (ME) extracts of A. paniculata against skin infection causing bacterial pathogens such as Staphylococcus aureus, Streptococcus pyogenes, Klebsiella pneumoniae, Enterobacter aerogenes, Proteus vulgaris, and Propionibacterium acnes. Also assessed the antidiabetic (α-glucosidase and α-amylase inhibition assay), antioxidant, and photoprotective potential of PE and ME extract analyses. The major bioactive compounds were identified and characterized through UV, FTIR, 1H-NMR and 13C-NMR spectra analyses. The ME extract contain more number of phytochemicals (alkaloids, flavonoids, saponins, terpenoids, glycoside, protein, and phytosterol) than PE extract. The antibacterial activity result also revealed that the ME (as dose dependent) extract showed better activity at 250 mg mL-1 as in the following order: P. acnes (6-29 mm) > K. pneumoniae (3-28 mm) > S. aureus (3-27 mm) > P. vulgaris (3-26 mm) > S. pyogenes (2-25 mm) > E. aerogenes (1-23 mm). PE: E. aerogenes (3-20 mm) > P. vulgaris (2-19 mm) > P. acnes (3-18 mm) > K. pneumoniae (3-17 mm) > S. aureus (2-16 mm) > S. pyogenes (0-11 mm). The MIC value of ME extract was found as 100-150 mg mL-1 and it was better than PE extract. Similarly, the ME also possesses dose based α-glucosidase inhibition activity as up to 85% at 250 mg mL-1 concentration. The fluorescence spectra analysis method also stated that the ME extract possess photoprotective bioactive agent. The ME fractions (F01 and F02) obtained from TLC and column chromatogram were identified as 3-O-β-d-glucosyl-14- deoxyandrographiside and 14-deoxyandrographolide respectively through UV, FTIR, 1H-NMR and 13C-NMR spectra analyses. Such compounds may be responsible for significant antibacterial activity against pathogenic bacteria causing skin infections, excellent antidiabetic activity, as well as photoprotective potential.

Impact Evaluations of Articles in Current Drug Delivery based on Web of Science

A total of 1534 and 308 articles were published in the journal Current Drug Delivery (CDD), from 2004 and 2019 to 2021, respectively. In this commentary, their impacts were analyzed based on search data about citation times in the Web of Science. These publications were categorized from different standpoints and evaluated in terms of their citations, particularly in the year 2021. The thematic, contemporary, and local features of these articles, as well as the article types and publication formats, were interpreted. Results demonstrated that CDD should be loyal to the contents about drug delivery, particularly nano-drug delivery systems and nano-pharmaceutical technologies. Publications from the developing and developed countries and regions showed no remarkable differences; therefore, submissions are similarly welcomed. Research articles and review articles are the main stream of CDD. The ratio of review papers is about 30%, which is reasonable but should not be further extended. Moreover, open publications with an article processing charge always have a high impact than those with subscription.

Oral nanomedicine biointeractions in the gastrointestinal tract in health and disease

Oral administration is the preferred route of administration based on the convenience for and compliance of the patient. Oral nanomedicines have been developed to overcome the limitations of free drugs and overcome gastrointestinal (GI) barriers, which are heterogeneous across healthy and diseased populations. This review aims to provide a comprehensive overview and comparison of the oral nanomedicine biointeractions in the gastrointestinal tract (GIT) in health and disease (GI and extra-GI diseases) and highlight emerging strategies that exploit these differences for oral nanomedicine-based treatment. We introduce the key GI barriers related to oral delivery and summarize their pathological changes in various diseases. We discuss nanomedicine biointeractions in the GIT in health by describing the general biointeractions based on the type of oral nanomedicine and advanced biointeractions facilitated by advanced strategies applied in this field. We then discuss nanomedicine biointeractions in different diseases and explore how pathological characteristics have been harnessed to advance the development of oral nanomedicine.

The Potential of Films as Transmucosal Drug Delivery Systems

Pharmaceutical films are polymeric formulations used as a delivery platform for administration of small and macromolecular drugs for local or systemic action. They can be produced by using synthetic, semi-synthetic, or natural polymers through solvent casting, electrospinning, hot-melt extrusion, and 3D printing methods, and depending on the components and the manufacturing methods used, the films allow the modulation of drug release. Moreover, they have advantages that have drawn interest in the development and evaluation of film application on the buccal, nasal, vaginal, and ocular mucosa. This review aims to provide an overview of and critically discuss the use of films as transmucosal drug delivery systems. For this, aspects such as the composition of these formulations, the theories of mucoadhesion, and the methods of production were deeply considered, and an analysis of the main transmucosal pathways for which there are examples of developed films was conducted. All of this allowed us to point out the most relevant characteristics and opportunities that deserve to be taken into account in the use of films as transmucosal drug delivery systems.

Multifunctional polysaccharide composited microneedle for oral ulcers healing

Oral ulcers have periodicity and recurrence, and the etiology and causative mechanisms remain unclear; therefore, it is difficult to treat oral ulcers effectively. Current clinical treatment methods mainly include pain relief and administration of anti-inflammatories to prevent secondary infections and a prolonged recurrence cycle. However, these traditional treatment methods are administered independently and are susceptible to muscle movements and constant salivary secretion in the mouth, resulting in ineffective drug functioning. Therefore, development of a novel treatment to reduce wound infection and accelerate wound healing for oral ulcers is required for effective treatment. Herein, we report a multifunctional polysaccharide composite microneedle patch based on hyaluronic acid (HA) and hydroxypropyl trimethyl ammonium chloride chitosan (HACC) loaded with dexamethasone (DXMS) and basic fibroblast growth factor (bFGF) for oral ulcer healing. DXMS and bFGF encapsulated the HA tip portion of the microneedle patch, endowing the microneedle patches with anti-inflammatory and angiogenic properties. HACC was applied to the back of the microneedle patch, adding antibacterial properties. The experimental results indicated that the prepared dressings exhibited good antibacterial activity and effectively promoted cell migration growth and angiogenesis. More importantly, animal experiments have shown that multifunctional microneedle patches can effectively promote oral ulcer healing. Thus, these novel multifunctional polysaccharide composite microneedle patches have great potential for oral ulcers treatment.

Dual-Step Controlled Release of Berberine Hydrochloride from the Trans-Scale Hybrids of Nanofibers and Microparticles

In this nano era, nanomaterials and nanostructures are popular in developing novel functional materials. However, the combinations of materials at micro and macro scales can open new routes for developing novel trans-scale products with improved or even new functional performances. In this work, a brand-new hybrid, containing both nanofibers and microparticles, was fabricated using a sequential electrohydrodynamic atomization (EHDA) process. Firstly, the microparticles loaded with drug (berberine hydrochloride, BH) molecules in the cellulose acetate (CA) were fabricated using a solution electrospraying process. Later, these microparticles were suspended into a co-dissolved solution that contained BH and a hydrophilic polymer (polypyrrolidone, PVP) and were co-electrospun into the nanofiber/microparticle hybrids. The EHDA processes were recorded, and the resultant trans-scale products showed a typical hybrid topography, with microparticles distributed all over the nanofibers, which was demonstrated by SEM assessments. FTIR and XRD demonstrated that the components within the hybrids were presented in an amorphous state and had fine compatibility with each other. In vitro dissolution tests verified that the hybrids were able to provide the designed dual-step drug release profiles, a combination of the fast release step of BH from the hydrophilic PVP nanofibers through an erosion mechanism and the sustained release step of BH from the insoluble CA microparticles via a typical Fickian diffusion mechanism. The present protocols pave a new way for developing trans-scale functional materials.

Multi-functional nanogel with cascade catalytic performance for treatment of diabetic oral mucosa ulcer

Introduction: Diabetic oral mucosa ulcers face challenges of hypoxia, hyperglycemia and high oxidative stress, which result in delayed healing process. Oxygen is regarded as an important substance in cell proliferation, differentiation and migration, which is beneficial to ulcer recovery. Methods: This study developed a multi-functional GOx-CAT nanogel (GCN) system for the treatment of diabetic oral mucosa ulcers. The catalytic activity, ROS scavenge and oxygen supply ability of GCN was validated. The therapeutic effect of GCN was verified in the diabetic gingival ulcer model. Results: The results showed that the nanoscale GCN was capable of significantly eliminating intracellular ROS, increasing intracellular oxygen concentration and accelerating cell migration of human gingival fibroblasts, which could promote diabetic oral gingival ulcer healing in vivo by alleviating inflammation and promoting angiogenesis. Discussion: This multifunctional GCN with ROS depletion, continuous oxygen supply and good biocompatibility, which might provide a novel therapeutic strategy for effective treatment of diabetic oral mucosa ulcers.

The influence of the ultrasonic treatment of working fluids on electrospun amorphous solid dispersions

Based on a working fluid consisting of a poorly water-soluble drug and a pharmaceutical polymer in an organic solvent, electrospinning has been widely exploited to create a variety of amorphous solid dispersions However, there have been very few reports about how to prepare the working fluid in a reasonable manner. In this study, an investigation was conducted to determine the influences of ultrasonic fluid pretreatment on the quality of resultant ASDs fabricated from the working fluids. SEM results demonstrated that nanofiber-based amorphous solid dispersions from the treated fluids treated amorphous solid dispersions exhibited better quality than the traditional nanofibers from untreated fluids in the following aspects: 1) a straighter linear morphology; 2) a smooth surface; and 3) a more evener diameter distribution. The fabrication mechanism associated with the influences of ultrasonic treatments of working fluids on the resultant nanofibers' quality is suggested. Although XRD and ATR-FTIR experiments clearly verified that the drug ketoprofen was homogeneously distributed all over the TASDs and the traditional nanofibers in an amorphous state regardless of the ultrasonic treatments, the in vitro dissolution tests clearly demonstrated that the TASDs had a better sustained drug release performance than the traditional nanofibers in terms of the initial release rate and the sustained release time periods.

Engineered Shellac Beads-on-the-String Fibers Using Triaxial Electrospinning for Improved Colon-Targeted Drug Delivery

Colon-targeted drug delivery is gradually attracting attention because it can effectively treat colon diseases. Furthermore, electrospun fibers have great potential application value in the field of drug delivery because of their unique external shape and internal structure. In this study, a core layer of hydrophilic polyethylene oxide (PEO) and the anti-colon-cancer drug curcumin (CUR), a middle layer of ethanol, and a sheath layer of the natural pH-sensitive biomaterial shellac were used in a modified triaxial electrospinning process to prepare beads-on-the-string (BOTS) microfibers. A series of characterizations were carried out on the obtained fibers to verify the process-shape/structure-application relationship. The results of scanning electron microscopy and transmission electron microscopy indicated a BOTS shape and core-sheath structure. X-ray diffraction results indicated that the drug in the fibers was in an amorphous form. Infrared spectroscopy revealed the good compatibility of the components in the fibers. In vitro drug release revealed that the BOTS microfibers provide colon-targeted drug delivery and zero-order drug release. Compared to linear cylindrical microfibers, the obtained BOTS microfibers can prevent the leakage of drugs in simulated gastric fluid, and they provide zero-order release in simulated intestinal fluid because the beads in BOTS microfibers can act as drug reservoirs.

Biphasic drug release from electrospun structures

INTRODUCTION

Biphasic release, as a special drug-modified release profile that combines immediate and sustained release, allows fast therapeutic action and retains blood drug concentration for long periods. Electrospun nanofibers, particularly those with complex nanostructures produced by multi-fluid electrospinning processes, are potential novel biphasic drug delivery systems (DDSs).

AREAS COVERED

This review summarizes the most recent developments in electrospinning and related structures. In this review, the role of electrospun nanostructures in biphasic drug release was comprehensively explored. These electrospun nanostructures include monolithic nanofibers obtained through single-fluid blending electrospinning, core-shell and Janus nanostructures prepared via bifluid electrospinning, three-compartment nanostructures obtained via trifluid electrospinning, nanofibrous assemblies obtained through the layer-by-layer deposition of nanofibers, and the combined structure of electrospun nanofiber mats with casting films. The strategies and mechanisms through which complex structures facilitate biphasic release were analyzed.

EXPERT OPINION

Electrospun structures can provide many strategies for the development of biphasic drug release DDSs. However, many issues such as the scale-up productions of complex nanostructures, the in vivo verification of the biphasic release effects, keeping pace with the developments of multi-fluid electrospinning, drawing support from the state-of-the-art pharmaceutical excipients, and the combination with traditional pharmaceutical methods need to be addressed for real applications.

Technological Aspects and Evaluation Methods for Polymer Matrices as Dental Drug Carriers

The development of polymer matrices as dental drug carriers takes into account the following technological aspects of the developed formulations: the composition and the technology used to manufacture them, which affect the properties of the carriers, as well as the testing methods for assessing their behavior at application sites. The first part of this paper characterizes the methods for fabricating dental drug carriers, i.e., the solvent-casting method (SCM), lyophilization method (LM), electrospinning (ES) and 3D printing (3DP), describing the selection of technological parameters and pointing out both the advantages of using the mentioned methods and their limitations. The second part of this paper describes testing methods to study the formulation properties, including their physical and chemical, pharmaceutical, biological and in vivo evaluation. Comprehensive in vitro evaluation of carrier properties permits optimization of formulation parameters to achieve prolonged retention time in the dynamic oral environment and is essential for explaining carrier behavior during clinical evaluation, consequently enabling the selection of the optimal formulation for oral application.

Fast and convenient delivery of fluidextracts liquorice through electrospun core-shell nanohybrids

Introduction: As an interdisciplinary field, drug delivery relies on the developments of modern science and technology. Correspondingly, how to upgrade the traditional dosage forms for a more efficacious, safer, and convenient drug delivery poses a continuous challenge to researchers.

Methods, results and discussion: In this study, a proof-of-concept demonstration was conducted to convert a popular traditional liquid dosage form (a commercial oral compound solution prepared from an intermediate licorice fluidextract) into a solid dosage form. The oral commercial solution was successfully encapsulated into the core–shell nanohybrids, and the ethanol in the oral solution was removed. The SEM and TEM evaluations showed that the prepared nanofibers had linear morphologies without any discerned spindles or beads and an obvious core–shell nanostructure. The FTIR and XRD results verified that the active ingredients in the commercial solution were compatible with the polymeric matrices and were presented in the core section in an amorphous state. Three different types of methods were developed, and the fast dissolution of the electrospun core–shell nanofibers was verified.

Conclusion: Coaxial electrospinning can act as a nano pharmaceutical technique to upgrade the traditional oral solution into fast-dissolving solid drug delivery films to retain the advantages of the liquid dosage forms and the solid dosage forms.

A Sequential Electrospinning of a Coaxial and Blending Process for Creating Double-Layer Hybrid Films to Sense Glucose

This study presents a glucose biosensor based on electrospun core-sheath nanofibers. Two types of film were fabricated using different electrospinning procedures. Film F1 was composed solely of core-sheath nanofibers fabricated using a modified coaxial electrospinning process. Film F2 was a double-layer hybrid film fabricated through a sequential electrospinning and blending process. The bottom layer of F2 comprised core-sheath nanofibers fabricated using a modified process, in which pure polymethacrylate type A (Eudragit L100) was used as the core section and water-soluble lignin (WSL) and phenol were loaded as the sheath section. The top layer of F2 contained glucose oxidase (GOx) and gold nanoparticles, which were distributed throughout the polyvinylpyrrolidone K90 (PVP K90) nanofibers through a single-fluid blending electrospinning process. The study investigated the sequential electrospinning process in detail. The experimental results demonstrated that the F2 hybrid film had a higher degradation efficiency of β-D-glucose than F1, reaching a maximum of over 70% after 12 h within the concentration range of 10-40 mmol/L. The hybrid film F2 is used for colorimetric sensing of β-D-glucose in the range of 1-15 mmol/L. The solution exhibited a color that deepened gradually with an increase in β-D-glucose concentration. Electrospinning is flexible in creating structures for bio-cascade reactions, and the double-layer hybrid film can provide a simple template for developing other sensing nanomaterials.

Piezoelectric Enhancement of Piezoceramic Nanoparticle-Doped PVDF/PCL Core-Sheath Fibers

Electrospinning is considered to be an efficient method to prepare piezoelectric thin films because of its ability to transform the phase of the polymers. A core-sheath structure can endow fibers with more functions and properties. In this study, fibers with a core-sheath structure were prepared using polyvinylidene fluoride (PVDF) included with nanoparticles (NPs) as the shell layer and polycaprolactone (PCL) as the core layer. Their mechanical and piezoelectric properties were studied in detail. During the course of the electrospinning process, PVDF was demonstrated to increase the amount of its polar phase, with the help of nanoparticles acting as a nucleating agent to facilitate the change. PCL was chosen as a core material because of its good mechanical properties and its compatibility with PVDF. Transmission electron microscope (TEM) assessments revealed that the fibers have a core-sheath structure, and shell layers were loaded with nanoparticles. Mechanical testing showed that the core layer can significantly improve mechanical properties. The XRD patterns of the core-sheath structure fibers indicated the β phase domain the main component. Piezoelectric testing showed that the doped nanoparticles were able to enhance piezoelectric performances. The increases of mechanical and piezoelectric properties of core-sheath structure fibers provide a feasible application for wearable electronics, which require flexibility and good mechanical properties.

Oral empagliflozin-loaded tri-layer core-sheath fibers fabricated using tri-axial electrospinning: Enhanced in vitro and in vivo antidiabetic performance

Empagliflozin (EM) was successfully loaded in polycaprolactone/poly (L-lactic acid)/polymethyl methacrylate (PCL/PLA/PMMA) fibers. In the rat β-cell line (BRIN-BD11), the insulin expression ratio of pancreatic β-cells was stimulated at high and low glucose by culturing with tri-layer EM-loaded fiber (EMF) for 48 h. The expression ratios of glucokinase and GLUT-2 proteins increased after EMF treatment. According to the in vitro drug release test, 97% of all drug contained in fibers was released in a controlled manner for 24 h. The pharmacokinetic test revealed that the bioavailability was improved ∼4.8-fold with EMF treatment compared to EM-powder and blood glucose level was effectively controlled for 24 h with EMF. Oral administration of EMF exhibited a better sustainable anti-diabetic activity even in the half-dosage than EM-powder in streptozotocin/nicotinamide-induced T2DM rats. The levels of GLP-1, PPAR-γ, and insulin were increased while the levels of SGLT-2 and TNF-α were decreased with EMF treatment. Also, EMF recovered the histopathological changes in the liver, pancreas, and kidney in T2DM rats and protected pancreatic β-cells. Consequently, EMF is suggested as an unprecedented and promotive treatment approach for T2DM with a higher bioavailability and better antidiabetic effect compared to conventional dosage forms.

Electrospun fibers with blank surface and inner drug gradient for improving sustained release

New engineering methods and advanced strategies are highly desired for creating novel drug sustained release nanomaterials. In this study, a trilayer concentric spinneret was explored to implement several multifluid electrospinning processes. A trilayer core-shell nanofiber was successfully fabricated, which comprise a drug-free polymeric coating and an inner drug gradient distribution, and then compared with bilayer core-shell and monolithic medicated nanofibers. All the electrospun nanofibers similarly consisted of two components (guest drug acetaminophen and host polymer cellulose acetate) and presented a linear morphology. Due to the secondary interactions within nanofibers, loaded drug with amorphous state was detected, as demonstrated by SEM, DSC, XRD, and FTIR determinations. In vitro and in vivo gavage treatments to rats tests were carried out, the trilayer nanofiber with an elaborate structure design were demonstrated to provide better drug sustained release profile than the bilayer core-shell nanofibers in term of initial burst release, later tail-off release and long sustained release time period. The synergistic mechanism for improving the drug sustained release behaviors is disclosed. By breaking the traditional concepts about the implementation of multifluid electrospinning and the strategy of combining surface properties and inner structural characteristics, the present protocols open a new way for developing material processing methods and generating novel functional nanomaterials.

Recent Progress of the Preparation and Application of Electrospun Porous Nanofibers

Electrospun porous nanofibers have gained a lot of interest recently in various fields because of their adjustable porous structure, high specific surface area, and large number of active sites, which can further enhance the performance of materials. This paper provides an overview of the common polymers, preparation, and applications of electrospun porous nanofibers. Firstly, the polymers commonly used to construct porous structures and the main pore-forming methods in porous nanofibers by electrospinning, namely the template method and phase separation method, are introduced. Secondly, recent applications of electrospun porous nanofibers in air purification, water treatment, energy storage, biomedicine, food packaging, sensor, sound and wave absorption, flame retardant, and heat insulation are reviewed. Finally, the challenges and possible research directions for the future study of electrospun porous nanofibers are discussed.

A Correlation Analysis between Undergraduate Students' Safety Behaviors in the Laboratory and Their Learning Efficiencies

Students' behaviors have a close relationship with their learning efficiencies, particularly about professional knowledge. Different types of behaviors should have different influences. Disclosing the special relationship between undergraduate students' conscious safety behaviors in their laboratory experiments with their learning efficiencies is important for fostering them into professional talents. In this study, a course entitled "Advanced Methods of Materials Characterization" was arranged to contain three sections: theoretical learning in the classroom, eight characterization experiments in the laboratory in sequence, and self-training to apply the knowledge. In the final examination, eighteen percent was allocated to the examination questions about safety issues. The students' scores for this section were associated with their total roll scores. Two quantitative relationships are disclosed. One is between the students' final examination score (y) and their subjective consciousness of safety behaviors (x) in their laboratory experiments, as y = 5.56 + 4.83 x (R = 0.9192). The other is between their grade point average (y) and safety behavior evaluation (x) as y = 0.51 + 0.15 x (R = 0.7296). Undergraduate students' behaviors in scientific laboratories need to be verified to have a close and positive relationship with their professional knowledge learning efficiencies. This offers a hint that improving students' safety behaviors and enhancing their subjective safety awareness are conducive to improving their learning efficiency for professional knowledge.

Progress of research on oral mucosal adhesive agents

Oral mucosal administration is extensively used to treat systemic diseases and oral mucosal diseases owing to unique oral mucosal structure and convenient administration. However, the special microenvironment of the oral cavity being open, moving, and humid causes oral mucosal drug delivery to face great challenges. To address this dilemma, local adhesive agents have been widely studied for sustained drug delivery and improved bioavailability, showing broad prospects. Recently, the author has performed studies on oral mucosal adhesive agents. In this paper, the progress of research on oral mucosal adhesive materials is reviewed.

Betamethasone-loaded dissolvable microneedle patch for oral ulcer treatment

Oral inflammatory disease (OID) is among the most common oral lesions, affecting people's quality of life and even leading to oral cancer. Oral ulcers are the most common OID. However, the pain and fear caused by the localized injection of hormones hinder the clinical treatment of oral ulcers. To address this problem, soluble hyaluronic acid (HA) microneedle patches (BSP-BDP@HAMN) containing betamethasone 21-phosphate sodium (BSP) and betamethasone 17,21-dipropionate (BDP) were fabricated for potential application in oral ulcers. BSP-BDP@HAMNs had the sufficient mechanical strength to penetrate the rat tongue abdomen mucosa with an insertion depth of approximately 207 ± 3 µm. The rapidly solubilized HA microneedle carrier released BSP and BDP into the ulcer base within 3 min of entering the mucosa. Cellular assays have shown that BDP@HAMNs have wound healing-promoting and anti-inflammatory effects. Compared with topical injections and creams, BSP-BDP@HAMNs not only penetrated the ulcer surface painlessly but also worked deep in the ulcer for a long time. In conclusion, the proposed BSP-BDP@HAMN patch can improve the comfort and efficacy of oral ulcer treatment, thus providing a new prospect for oral ulcer treatment.

Bio-Inspired Drug Delivery Systems: From Synthetic Polypeptide Vesicles to Outer Membrane Vesicles

Nanomedicine is a broad field that focuses on the development of nanocarriers to deliver specific drugs to targeted sites. A synthetic polypeptide is a kind of biomaterial composed of repeating amino acid units that are linked by peptide bonds. The multiplied amphiphilicity segment of the polypeptide could assemble to form polypeptide vesicles (PVs) under suitable conditions. Different from polypeptide vesicles, outer membrane vesicles (OMVs) are spherical buds of the outer membrane filled with periplasmic content, which commonly originate from Gram-negative bacteria. Owing to their biodegradability and excellent biocompatibility, both PVs and OMVs have been utilized as carriers in delivering drugs. In this review, we discuss the recent drug delivery research based on PVs and OMVs. These related topics are presented: (1) a brief introduction to the production methods for PVs and OMVs; (2) a thorough explanation of PV- and OMV-related applications in drug delivery including the vesicle design and biological assessment; (3) finally, we conclude with a discussion on perspectives and future challenges related to the drug delivery systems of PVs and OMVs.

Electrospun self-emulsifying core-shell nanofibers for effective delivery of paclitaxel

The poor solubility of numerous drugs pose a long-existing challenge to the researchers in the fields of pharmaceutics, bioengineering and biotechnology. Many "top-down" and "bottom-up" nano fabrication methods have been exploited to provide solutions for this issue. In this study, a combination strategy of top-down process (electrospinning) and bottom-up (self-emulsifying) was demonstrated to be useful for enhancing the dissolution of a typical poorly water-soluble anticancer model drug (paclitaxel, PTX). With polyvinylpyrrolidone (PVP K90) as the filament-forming matrix and drug carrier, polyoxyethylene castor oil (PCO) as emulsifier, and triglyceride (TG) as oil phase, Both a single-fluid blending process and a coaxial process were utilized to prepare medicated nanofibers. Scanning electron microscope and transmission electron microscope (TEM) results clearly demonstrated the morphology and inner structures of the nanofibers. The lipid nanoparticles of emulsions after self-emulsification were also assessed through TEM. The encapsulation efficiency (EE) and in vitro dissolution tests demonstrated that the cores-shell nanofibers could provide a better self-emulsifying process int terms of a higher EE and a better drug sustained release profile. Meanwhile, an increase of sheath fluid rate could benefit an even better results, suggesting a clear process-property-performance relationship. The protocols reported here pave anew way for effective oral delivery of poorly water-soluble drug.

Recent Progress of Electrospun Herbal Medicine Nanofibers

Herbal medicine has a long history of medical efficacy with low toxicity, side effects and good biocompatibility. However, the bioavailability of the extract of raw herbs and bioactive compounds is poor because of their low water solubility. In order to overcome the solubility issues, electrospinning technology can offer a delivery alternative to resolve them. The electrospun fibers have the advantages of high specific surface area, high porosity, excellent mechanical strength and flexible structures. At the same time, various natural and synthetic polymer-bound fibers can mimic extracellular matrix applications in different medical fields. In this paper, the development of electrospinning technology and polymers used for incorporating herbal medicine into electrospun nanofibers are reviewed. Finally, the recent progress of the applications of these herbal medicine nanofibers in biomedical (drug delivery, wound dressing, tissue engineering) and food fields along with their future prospects is discussed.

Development of Verapamil Hydrochloride-loaded Biopolymer-based Composite Electrospun Nanofibrous Mats: In vivo Evaluation of Enhanced Burn Wound Healing without Scar Formation

Introduction

Researchers aim for new heights in wound healing to produce wound dressings with unique features. Natural, synthetic, biodegradable, and biocompatible polymers especially in the nanoscale are being employed to support and provide efficient wound management. Economical and environmentally friendly sustainable wound management alternatives are becoming an urgent issue to meet future needs. Nanofibrous mats possess unique properties for ideal wound healing. They mimic the physical structure of the natural extracellular matrix (ECM), promote hemostasis, and gas permeation. Their interconnected nanoporosity prevents wound dehydration and microbial infiltration.

Purpose

To prepare and evaluate a novel verapamil HCl-loaded environmentally friendly composite, with biopolymer-based electrospun nanofibers suitable for application as wound dressings providing adequate wound healing with no scar formation.

Methods

Composite nanofibers were prepared by electrospinning of a blend of the natural biocompatible polymers, sodium alginate (SA) or zein (Z) together with polyvinyl alcohol (PVA). Composite nanofibers were characterized in terms of morphology, diameter, drug entrapment efficiency, and release. In vivo study of the therapeutic efficacy of verapamil HCl-loaded nanofibers on a Sprague Dawley rat model with dermal burn wound was investigated in terms of percent wound closure, and presence of scars.

Results

Combining PVA with SA or Z improved the electrospinnability and properties of the developed nanofibers. Verapamil HCl-loaded composite nanofibers showed good pharmaceutical attributes favorable for wound healing including, fiber diameter ∼150 nm, high entrapment efficiency (∼80-100%) and biphasic controlled drug release for 24 h. In vivo study demonstrated promising potentials for wound healing without scaring.

Conclusion

The developed nanofibrous mats combined the beneficial properties of the biopolymers and verapamil HCl to provide an increased functionality by exploiting the unique advantages of nanofibers in wound healing at a small dose proved to be insufficient in case of the conventional dosage form.

Progress of Electrospun Nanofibrous Carriers for Modifications to Drug Release Profiles

Electrospinning is an advanced technology for the preparation of drug-carrying nanofibers that has demonstrated great advantages in the biomedical field. Electrospun nanofiber membranes are widely used in the field of drug administration due to their advantages such as their large specific surface area and similarity to the extracellular matrix. Different electrospinning technologies can be used to prepare nanofibers of different structures, such as those with a monolithic structure, a core-shell structure, a Janus structure, or a porous structure. It is also possible to prepare nanofibers with different controlled-release functions, such as sustained release, delayed release, biphasic release, and targeted release. This paper elaborates on the preparation of drug-loaded nanofibers using various electrospinning technologies and concludes the mechanisms behind the controlled release of drugs.

Advances in the Preparation of Nanofiber Dressings by Electrospinning for Promoting Diabetic Wound Healing

Chronic diabetic wounds are one of the main complications of diabetes, manifested by persistent inflammation, decreased epithelialization motility, and impaired wound healing. This will not only lead to the repeated hospitalization of patients, but also bear expensive hospitalization costs. In severe cases, it can lead to amputation, sepsis or death. Electrospun nanofibers membranes have the characteristics of high porosity, high specific surface area, and easy functionalization of structure, so they can be used as a safe and effective platform in the treatment of diabetic wounds and have great application potential. This article briefly reviewed the pathogenesis of chronic diabetic wounds and the types of dressings commonly used, and then reviewed the development of electrospinning technology in recent years and the advantages of electrospun nanofibers in the treatment of diabetic wounds. Finally, the reports of different types of nanofiber dressings on diabetic wounds are summarized, and the method of using multi-drug combination therapy in diabetic wounds is emphasized, which provides new ideas for the effective treatment of diabetic wounds.

The Applications of Ferulic-Acid-Loaded Fibrous Films for Fruit Preservation

The aim of this study was to develop a novel ultrathin fibrous membrane with a core-sheath structure as an antioxidant food packaging membrane. The core-sheath structure was prepared by coaxial electrospinning, and the release of active substances was regulated by its special structure. Ferulic acid (FA) was incorporated into the electrospun zein/polyethylene oxide ultrathin fibers to ensure their synergistic antioxidant properties. We found that the prepared ultrathin fibers had a good morphology and smooth surface. The internal structure of the fibers was stable, and the three materials that we used were compatible. For the different loading positions, it was observed that the core layer ferulic-acid-loaded fibers had a sustained action, while the sheath layer ferulic-acid-loaded fibers had a pre-burst action. Finally, apples were selected for packaging using fibrous membranes to simulate practical applications. The fibrous membrane was effective in reducing water loss and apple quality loss, as well as extending the shelf life. According to these experiments, the FA-loaded zein/PEO coaxial electrospinning fiber can be used as antioxidant food packaging and will also undergo more improvements in the future.

Electrospun Porous Nanofibers: Pore−Forming Mechanisms and Applications for Photocatalytic Degradation of Organic Pollutants in Wastewater

Electrospun porous nanofibers have large specific surface areas and abundant active centers, which can effectively improve the properties of nanofibers. In the field of photocatalysis, electrospun porous nanofibers can increase the contact area of loaded photocatalytic particles with light, shorten the electron transfer path, and improve photocatalytic activity. In this paper, the main pore−forming mechanisms of electrospun porous nanofiber are summarized as breath figures, phase separation (vapor−induced phase separation, non−solvent−induced phase separation, and thermally induced phase separation) and post−processing (selective removal). Then, the application of electrospun porous nanofiber loading photocatalytic particles in the degradation of pollutants (such as organic, inorganic, and bacteria) in water is introduced, and its future development prospected. Although porous structures are beneficial in improving the photocatalytic performance of nanofibers, they reduce their mechanical properties. Therefore, strategies for improving the mechanical properties of electrospun porous nanofibers are also briefly discussed.